Add an additional contact to your Hostkey account. Since it starts with a random email, update the email address in Invapi before use.
Add an additional contact to the account (whmcs/add_contact). WARNING: the contact is created with a random email — change it in Invapi.
| Name | Required | Description | Default |
|---|---|---|---|
| confirm | Yes | Must be true to run the operation. |
Changes observed during successful MCP inspections.
v1.0.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the safety profile (not read-only, not destructive, open-world), so the description's job is to add what they don't cover. It does exactly that by disclosing a genuinely non-obvious side effect: the contact is created with a random email and must be corrected in Invapi. Auth/rate-limit details are still absent, so not a 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences, zero filler, with the action stated first and the critical WARNING front-loaded where an agent will not miss it.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a one-parameter mutation with no output schema, the definition covers what it does, the target system, and the key gotcha. It stops short of explaining which account scope is used or what the call returns, but nothing essential to calling it correctly is missing.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
There is only one parameter and the schema documents it fully ('Must be true to run the operation'), so the schema carries the load. The description adds no extra meaning about 'confirm', which is the correct baseline when coverage is 100%.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb and resource ('Add an additional contact to the account') and even names the underlying endpoint (whmcs/add_contact). The word 'additional' implicitly separates it from update_contact/delete_contact, but no sibling is named explicitly.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description never says when to reach for this versus update_contact, get_contacts, or delete_contact, nor what prerequisites (a valid account/client) are needed. The only workflow hint is the post-creation fix-up, which is a behavioral caveat rather than usage guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.